震前电离层TEC异常探测方法研究

STUDY ON METHOD OF DETECTING IONOSPHERIC TEC ANOMALY BEFORE EARTHQUAKE

考虑到震前电离层TEC异常扰动探测方法(主要包括平均数法、中位数法、四分位距法等)的局限性,提出采用电离层TEC拟合后的剩余残差来识别TEC异常,即先对电离层TEC时间序列进行拟合,然后利用滑动时窗法进行异常识别。基于中国地壳运动观测网络GNSS观测资料解算的电离层TEC数据,采用上述方法对汶川8.0级大地震进行分析,结果显示该方法能够合理有效地探测到震前电离层TEC的异常扰动。

Considering the limitations of available methods including the method on median and the Inter Quartile Range （IQR） ,etc. for detecting the abnormal TEC disturbance of ionosphere before earthquake, the paper put forword an improved method to distinguish the TEC anomaly by use of residual error after fitting the ionospheric TEC, i. e. At first, fitted the time sequence of ionospheric TEC and then distinguished the anomaly with sliding window method. On the basis of the GNSS observation data from the reference stations of Crustal Movement Observational Network of China, the continuous 31-day TEC values over China were computed and the data of Wenchuan Ms8.0 earthquake in Sichuan province on May 12th 2008 were analyzed, the results shows that the ionospheric TEC anomaly obtained with the method is reasonable and effective.